Do not use rustup-components-history

It sometimes stops: rust-lang/rustup-components-history#34

Author: taiki-e

.github/workflows/ci.yml

@@ -256,12 +256,8 @@ jobs:
   #   runs-on: ubuntu-latest
   #   steps:
   #     - uses: actions/checkout@v2
-  #     - name: Install Rust and Clippy
-  #       run: |
-  #         toolchain=nightly-$(curl -sSf https://rust-lang.github.io/rustup-components-history/x86_64-unknown-linux-gnu/clippy)
-  #         rustup set profile minimal
-  #         rustup default "$toolchain"
-  #         rustup component add clippy
+  #     - name: Install Rust
+  #       run: rustup toolchain install nightly --component clippy && rustup default nightly
   #     - run: cargo clippy --workspace --all-features --all-targets
 
   fmt: